Must have been an old hard drive. They were making solid state recorders by 2000. Also, the flight recorder case is supposed to be air tight, and waterproof to a specified depth. L-3 was making them when they bought Microdyne. They were also building solid state replacements for the old 70 MHz analog recorders used to log telemetry data.
My spectrum analyzer shows that some of my Chinese aftermarket laptop power supplies do emit measurable RF up to about 50MHz. The Dell OEM ones are considerably quieter. Of course a laptop can run without a power supply.
-M90r7t
" snipped-for-privacy@krl.org" fired this volley in news: snipped-for-privacy@googlegroups.com:
That's just to make sure they didn't miss any on the first two times through. They likely also required a different person to do each over- write.
It's like redundancy on aircraft systems; better safe than sorry.
LLoyd
The hate for the Chinese that some exhibit is unreasonable.
=====
I don't hate them. I've worked with and for several Chinese engineers and greatly respect their abilities. It's their government's motives that I distrust.
Sun-tzu on war with the USA:
Cool.
Best fun way to destroy a disk:
Thermite bomb.
Set on top, pull the pin. Scrape up the puddle when its all over.
Standard issue in spy kits and STRATCOM data centers.
We'd have to over write all disk sectors three times with 1's & 0's to declassify hard disks. Took 1,000 times of over writing to declassify the core memory boards.
RF leakage was our big problem. Could not put any holes through the metal walls/floor/roof.
Fun times.
"Jim Wilkins" fired this volley in news:lc36bs$vap$1 @dont-email.me:
And the hate that the rest exhibit is perfectly reasonable.
I take it you've not had to deal _directly_ with them, yes?
LLoyd
Yes as individuals, no as official corporate representatives, other than incoming inspection. I didn't see any great difference between dealing with them and natives of Germany, Argentina, France, Nigeria, Switzerland, Japan, Haiti, Thailand, Spain, Cambodia, Russia, Vietnam, Britain, Ukraine, Israel, India, and wherever else I've forgotten. The New England electronics industry is very multinational.
No comment.
I've seen a screen room shielded with chicken wire, though usually they were nearly watertight.
FCC Class B standards are pretty good at minimizing conducted and radiated emissions, as long as the product actually complies with them.
Decades ago I worked on Trident drive systems that used. 10" and 12" open platters .. A whopping 200 Kb per platter.
"Jim Wilkins" fired this volley in news:lc39d8$h6m $ snipped-for-privacy@dont-email.me:
When we built our new multi-miniframe site in Daytona Beach, we constructed a Faraday Cage around the main computer room (all DG Novas and Point-4 systems). This wasn't for Tempest protection, but to prevent interference with radios and audio equipment in other rooms of the facility. At the time, everything was 7400-series logic, and emitted a LOT of RF noise. We had a tech who programmed a memory test routine that played Jingle Bells on any radio unfortunate enough to be in range of the CPU.
LLoyd
"Thanks for all the free stuff -TeaBillies !" fired this volley in news: snipped-for-privacy@googlegroups.com:
Heh! Back in the early-mid 90s, I bought one of the two Apollo launch- control computers from the Cape on a junk sale ($400). It filled my entire two-car garage.
It was a Systems Engineering Labs 840 (SEL-840 badge) that had two IBM _true_ 3030 drives... five platters, 1MB total! The original "Winchester" technology.
LLoyd
I recall seeing something similar in Russia around 1985.
iIgnoramus15922 fired this volley in news:u7SdncjMl7zlr3jPnZ2dnUVZ snipped-for-privacy@giganews.com:
Heh! The US more-or-less retired that original 3030 technology about 1971! The first disk drives I ever worked on professionally were Xerox Diablo
33s... 2.5MB per platter, removable media. In five years, we were up to 80MB drives, and it never stopped increasing exponentially since then.LLoyd
I do not recall the capacity of the drives that I saw. But they were about 20" in diameter.
i
There was no requirement to have different people do each over write. As I remember the program would do three over writes when ever it was run. I a lways believed the requirement for three over writes was because of the res idual magnetism after one write was possibly enough to be able to reconstr uct the data. It would take some sophisticated equipment to do that, but it would be theoretically possible.
Dan
" snipped-for-privacy@krl.org" fired this volley in news: snipped-for-privacy@googlegroups.com:
That's one of those "old wive's tales". It takes a certain minimum flux to flip a magnetic dipole. You can't 'write' data without flipping the dipoles. Once done, it's done. There are no 'phantom bits' remaining after a write.
There surely MAY be bits that never got written, but that's a different issue.
Lloyd
Hah! I worked on a SEL 32/55 in the late 1970s to early 1980s. It would also fill a garage, and required repair once a week.
Joe Gwinn
The old Baird Gamma Cameras that my friend Terry maintained (and I helped do P/M work on) had hard drives with removable 14" discs. Double-sided, they held a whole megabyte of data!
Nowadays, we can buy and cram -terabytes- into a 2.5" drive package.
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